Control of serum protein production in hepatocyte hybridomas: immortalization and expression of normal hepatocyte genes.

Publisher Website
Google Scholar
Abstract
Hepatocyte hybridomas were isolated after fusion of adult hepatocytes and .alpha.-fetoprotein (AFP)-producing mouse hepatoma cells. The yield of viable hybrid clones was low but could be increased by culturing the cells in the presence of insulin. On the basis of their chromosome constitution, the hybrids were classified into 2 groups characterized by either a single or a double set of mouse (hepatoma) chromosomes. The hybrids segregated rat chromosomes and thus constitute an excellent material for gene mapping studies in the rat. Most of the hepatocyte hybridomas retained the production of one or more rat serum proteins, indicating that the corresponding structural genes, contributed by the normal hepatocyte parent, have been immortalized and maintained in the active state after fusion. These hybrids do not produce rat AFP, although mouse AFP synthesis is maintained. Silent rat (hepatocyte) AFP genes apparently coexist in hepatocyte hybridoma nuclei with active mouse (hepatoma) AFP genes. On the basis of certain properties of these hepatocyte-hepatoma hybrids, the nondividing state of the hepatocytes is actively controlled by a regulatory mechanism which prevents DNA synthesis or entry into mitosis or both.